PRICES,SPATIAL COMPETITION AND HETEROGENEOUS PRODUCERS: AN EMPIRICAL TEST*

Homogeneous‐producer models attribute lower prices in denser markets solely to lower optimal markups. I argue here that when producers have different production costs, competition‐driven selection on costs also reduces prices. This selection mechanism can be distinguished from the homogenous‐producer case because it implies that higher density leads not only to lower average prices, but to declines in upper‐bound prices and price dispersion as well. I find empirical support for this mechanism in the prices of ready‐mixed concrete plants. I also show these findings do not simply reflect lower factor prices in dense markets, but result instead because dense‐market producers are more efficient.